JPS5915703A - Vertical type high-pressure feedwater preheater of header structure with heat remover and separator for steam and water - Google Patents

Abstract

A steam duct (5) enclosing the preheater tube-bundle (6) leads, upwards, from the desuperheater box (2) and via a deflecting quarter-bend (9), opens into a flat steam-distribution duct (8). The heating steam flows from this distribution duct (8), through steam outlet openings (12) on the vertical narrow sides (11), and thereafter flows radially through the preheater tube-bundles (6), from the outside to the inside.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention is a vertical high-pressure supply water heater (so-called heater) having a header structure and having a heat remover (so-called heat exchanger), which is provided within the range of a preheater tube bundle. Equipped with a steam and water separation device,
The present invention relates to a type in which a heat removal case surrounds a supply water outlet collecting pipe.

In thermal power plants, the feed water under overpressure is heated in a high-pressure preheater by scavenging air from the turbine to a desired final boiler feed temperature.

Generally, the scavenging air is superheated steam, and a portion of its excess heat is transferred to the feed water in a heat remover, which is the final member of the preheater tube bundle, viewed in the direction of flow of the feed water to be heated. At this time, the baffle plate forms a steam flow path along the feed water pipe within the heat remover. In this case, the steam reaches the condensation location at the end of the countercurrent forming portion of the supply water pipe bundle and drips there.

Therefore, at the outlet of the steam from the heat remover, the steam collides with the condensate dripping from the tube bundle under the locally high steam velocity, resulting in erosion loss to the preheater. This puts each tube of the preheater at risk whether it has a rising steam flow or a falling steam flow.

Some known feed water heaters are equipped with an upwardly open or only partially closed heat remover, in which case the steam flows upwardly at a high velocity and drains the preheater. The condensate that forms in the upper part is entrained upwards, where it also causes erosion. In order to reduce the rate of steam exit from the heat rejecter, it is conventional to further provide an opening in the separating wall between the heat rejection chamber and the condensate chamber, which short-circuits a portion of the steam flow and short-circuits the remainder. The aim is to reduce the velocity of the steam to such an extent that said erosion is sufficiently avoided.

However, this measure causes strong erosive effects in the condensate zone, since the steam entering through the openings is forced to impinge on much larger condensate droplets than in the upper part of the preheater tube bundle. .

The object of the invention is to largely avoid the collision of steam with downwardly dripping condensate in the range of high steam velocities and the resulting erosion losses, and to prevent the erosion losses that normally occur also in the tube supports. That's true.

Furthermore, it is necessary to prevent condensate from falling into the heat remover, especially during normal operation, during load changes and during boiler installation interruptions, since these phenomena impair the thermodynamic effectiveness of the heat remover. be.

It is therefore necessary to separate steam and water at all points where their collision could cause erosion.

A further object of the invention is to reduce as much as possible the assembly costs of the rejector part, which is cross-connected at right angles to the longitudinal extension of the preheater tube bundle and isolates the tube bundle from the steam guide channel. Moreover, compared to the prior art, only a small number of easily accessible locations are required for welding.

According to the present invention, the second problem can be solved by providing a steam guide passage branching from the heat remover case and extending upward, and the steam guide passage branching from the heat removal case and extending upward, and the steam guide passage being viewed from the flow direction of the supply water of the preheater tube bundle. and substantially air-tightly surrounds a portion of the length of the last straight section, and a deflection pen P is connected to the upper end of the steam guide passage, and the deflection pen P is connected in the steam distribution passage. a flat case member, which guideably connects the passage to the steam guide passage, the steam distribution passage extending along the free space between two mutually adjacent straight sections of the preheater tube bundle; The two vertical narrow sides of this vapor distribution passage are provided with a plurality of vapor outlet openings distributed over their height, and the lower horizontal side of the vapor distribution passage is provided with a plurality of vapor outlet openings distributed over its height. The narrow surface was achieved in that it was designed as a steam outlet slit over its entire length.

゛Next, the present invention will be explained with reference to the illustrated embodiments.

In the figure, a vertical high-pressure supply water heater according to the present invention is shown with the condensate collecting pipe disposed below the heat remover J removed. The main components of the heat remover 1 are a heat remover case 2 to which the steam artificial pipe piece 3 is attached and which receives the feed water outlet collecting pipe 4, and a preheater tube bundle 6, viewed from the feed water flow direction. a steam guide passage 5 extending upwardly including a last straight section 7; a steam distribution passage 8; and a diversion connecting said passage to the steam distribution passage 8 at the upper end of the steam guide passage 5. ben 159
It consists of. The steam distribution channel 8 is shallow and forms a separating wall between the last straight section 7 and the penultimate straight section 1o of the preheater tube bundle. The vertical narrow faces J1 of both steam distribution channels 80 are formed with rows of steam outlet openings 12 distributed over the entire height, whereas the upper horizontal narrow faces 13 are closed and the lower horizontal faces J1 are closed. The horizontal narrow side surface is open over the entire width and has an elongated steam outlet slit 14.
is formed. Above the deflection bend 9, a horizontal condensate collection plate 15 is fitted in the steam distribution channel 8.

Several support points 16 are arranged inside the steam guide channel 5, to which the respective serpentine tubes of the preheater tube bundle 6 are fastened in a known manner, i.e. each serpentine tube is fixed with respect to its longitudinal extension. It is completely fixed in position at right angles, and can freely slide in the longitudinal direction ↑ so as not to interfere with thermal expansion.

This heat remover 1 includes a condensate collection plate 15 and a 4-inch P9 for changing direction.
The upper closure plate and the other welded thin plate structure ↑
be. The connection of this closure plate, designated 17, to the vertical wall of the heat sink is shown in FIGS. 8 and 9. The closing plate 17 is simply welded with its four edges to the three walls of the steam guide channel 50 and to one wall of the steam distribution channel 8. The closure plate 17 and the condensate collection plate 1.]5 are assembled from several parts in such a way as to allow a very simple attachment of the preheater tube bundle 6 to each serpentine tube. Each closing plate member 18 forming the closing plate 17 is shown in FIGS. 3 to 5, and the condensate collecting plate member j9 is shown in a side view and a plan view from above, respectively, in FIGS. 6 and 7. and is shown.

As can be seen from FIGS. 3 to 5, the closure plate member 1
The width of 8 is the same as the axial spacing of two adjacent tube rows. Furthermore, a plurality of semicircular notches 2o are distributed over the length of the two vertically oriented longitudinal edges of the member 18, through which the 6 of the preheater tube bundle 6 is inserted. A tube 21 is guided through it. In FIG. 4 two adjacent closure plate members 18 are shown, and in FIG. 5 a portion of one closure plate member 18 is shown.

The installation of the preheater tube bundle 6 is sometimes carried out by placing each set of serpentine tubes into respective notches 20 of the first closure plate member 18, followed by the installation of the second member 18, and finally the completion of its assembly. The closed plate is welded into the thin plate structure of the heat remover as described above.

As can be seen in FIGS. 3 and 8, each closing plate member 18 in the transition from the outer vertical wall 22 of the steam guide channel 5 to the horizontal section of the closing plate 17 has a curved portion 23 on its underside; It has a diagonally chamfered portion 24 on its upper surface.

The curvature 23 serves to advantageously divert the flow of steam from the steam guide passage 5 to the steam distribution passage 8, thereby preventing the formation of stagnant steam zones that promote erosion and form condensate. The diagonal chamfer 24 functions to drain condensate accumulated on the upper surface.

As can be seen in FIG. 1, the condensate collection plate 15 is welded to the wall of the steam distribution channel 8 above the closure plate 17 and is formed from the parts 19 shown in FIGS. 6 and 7. has been done. After the condensate collection plate 15 has been assembled from the parts 19, a drip strip 25 is welded to its free end, which prevents condensate from dripping downward onto the closure plate. ing. Further, the dripping strip 25 is connected to each part 8.
19 at its free end.

The functional advantage of this heat remover structure is that the steam entering the steam distribution passage 8 via the steam guide passage 5 is uniformly distributed and directed to the narrow face 11 and each steam outlet of the narrow face It flows out through the opening 12 and flows radially from the outside to the inside into the preheater tube bundle 6 and condenses. A portion of the steam flows downwardly through the steam outlet slit 14. This slot 14 also serves to discharge condensate generated in the steam distribution passage 8.

According to the heat remover of the present invention, it is possible to reliably separate two flow phases: steam flowing out from the steam distribution passage 8 and water flowing down from the condensate formation surface, that is, from the side part of the preheater tube bundle. .

[Brief explanation of drawings]

The drawings show one embodiment of the present invention, in which FIG. 1 is a schematic vertical sectional view of a vertical high-pressure water heater according to the present invention, and FIG. 2 is a cross-sectional view taken along line n-II in FIG. cross section along the line,
Figures 3, 4, and 5 are side views and top plan views of the closure plate member, and Figures 6 and 7 are side views and top plan views of the condensate collection plate member. Figure, Figure 8. FIG. 9 shows a side view and a plan view from above of a portion of the steam guide passage of the heat remover together with the closing plate.

Claims (1)

[Scope of Claims] 1. A vertical high-pressure supply water heater with a header structure having a heat remover, which is equipped with a steam and water separation device within a preheater tube bundle, and has a heat removal device. A heat removal case (2) in a type where the heating case surrounds the supply water outlet collecting pipe.
A steam guide channel (5) is provided which branches off from and extends upwardly, which steam guide channel (5) extends from the last straight section (7) of the preheater tube bundle (6) in the feed water flow direction. ), and substantially airtightly surrounds a portion of the length of the steam guide passage (
A diverting bend (9) is connected to the upper end of 5), which diverting bend (9) connects into the steam distribution passage (8) and connects the passage (8) to the steam guiding passage (5). a flat steam distribution channel (8) extending along the free space between two mutually adjacent straight sections (7, 10) of the preheater tube bundle (6); The vapor distribution channel (8) is formed as a housing part and has a plurality of vapor outlet openings (12) arranged in the two vertical narrow sides (11) and distributed over its height; Further, the horizontal narrow surface on the lower side of the steam distribution passage is formed as a steam outlet (14) over its entire length, and is equipped with a heat remover and a steam and water separation device. A vertical high-pressure water heater with a header structure. 2. A closing plate (17) forms two horizontal limits of the turning r (9), and this closing plate (17)
7) through which each tube (21) of the preheater tube bundle (6) extends into the steam guide passage (5), said closing plate) (1
7) is assembled from a plurality of rod-shaped closing plate members (18), the width of the closing plate member (1B) is the same as the axial spacing of two adjacent tube rows, and the closing plate member ( A plurality of semicircular notches (20) are distributed over the length of both longitudinal edge surfaces of the pipe (18) facing in the vertical direction, and the radius of the notches (20) is the same as that of the pipe (21). 2. A high-pressure feed water heater according to claim 1, wherein the outer diameter of the high-pressure water heater is equal to half of the outer diameter of 3 Steam guide passage (5) of the closing plate member (18)
A curved portion (23) is formed on the side facing the inside of the
A closing plate (17) is welded with its horizontal outer edge to the thin plate wall of the steam guide passage (5), and an oblique chamfer (24) is formed on the upper surface of the closing plate (17). A high-pressure supply water heater according to claim 2. 4. Above the closure plate (17), a condensate collection plate (15) assembled from a plurality of rod-shaped condensate collection plate members (19) is welded to the steam distribution channel (8); The width of this condensate collection plate member (19) is the same as the axial spacing of two adjacent tube rows, and both longitudinal edge surfaces of the condensate collection plate member (19) facing in the vertical direction A plurality of semicircular notches (20) are distributed over its length, the radius of the notches (20) being equal to the radius of the tube (21).
), and the free end of each condensate collection plate member (9) is connected to the N: by a drip strip (25) welded to the lower surface of that part has been,
A high-pressure supply water heater according to claim 1.